Signals Research Group has put FDD Massive MIMO under an independent spotlight. Its latest live-network tests examined 5G Massive MIMO and MU-MIMO in commercial FDD spectrum. The work took place on Verizon cells in St. Paul, Minnesota. Ericsson supplied the radio equipment for the tested network.
The findings matter because operators need more value from existing spectrum. Massive MIMO uses many antennas to improve coverage and capacity. MU-MIMO lets multiple devices share the same radio resources. Together, they can increase network efficiency without new spectrum.
However, FDD makes this task harder than TDD. TDD uses one channel for uplink and downlink timing. That helps the network understand radio conditions more easily. FDD separates uplink and downlink frequencies. So, the network must work harder to manage each device.
That technical challenge made the results notable. SRG found strong gains after Verizon moved from 4T4R to 32T32R Massive MIMO. The additional use of MU-MIMO delivered a major uplink lift. The group described uplink throughput improvement as “simply outstanding.”
The tests used two Motorola razr fold 2026 smartphones. They were locked to 5G Standalone operations in Band n2. SRG also used tools from Accuver Americas and Keysight Technologies. Testing included fixed positions and walk routes across multiple cells.
The uplink results were especially consistent. SRG said uplink MU-MIMO occurred nearly all the time. The network delivered close to four uplink MIMO layers regularly. That happened even when the two phones were placed close together.
This result challenges a common assumption. Engineers often expect MU-MIMO to work better with device separation. More distance helps the network distinguish users. Yet SRG saw resource sharing with phones only 18 inches apart. Mike Thelander noted, “Now, I’ve seen that in TDD. I didn’t expect to see that in FDD.”
The downlink story was less uniform. SRG found that Massive MIMO already performed well using SU-MIMO. In some routes, downlink MU-MIMO delivered solid double-digit efficiency gains. In other routes, device pairing was less stable. Thelander called downlink MU-MIMO “hit or miss, relative to what you already got with the Massive MIMO.”
Even so, the trial points to meaningful network potential. FDD spectrum remains widely used by mobile operators worldwide. Better uplink performance can improve video sharing, cloud apps, and enterprise mobility. It can also help operators delay costly spectrum expansion.
Yet broader deployment will require more proof. SRG tested an unloaded cell with only two devices. Real networks handle many moving users and changing traffic conditions. Still, the results suggest FDD MU-MIMO may scale better than expected. For network planners, that makes this trial worth close attention.
